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This study conducts a literature review coupled with case-study calculations comparing the thermal contribution of semi-intensive and intensive (deeper) green roofs to non-insulated and insulated building roofs, and enhancing comprehension by validating applied scenarios with published literature-based data. Mitigation of the urban heat island is crucial for reducing energy consumption and enhancing urban sustainability, especially through natural solutions such as green (i.e., planted) roofs. The energy and environmental benefits of green roofs include energy conservation, thermal comfort, noise reduction, and aesthetic improvement. Legal mandates, innovative business models, financial subsidies and incentives, regulations, etc. are all components of green roof policies. Conflicts between private property owners and the public, regulatory gaps, and high installation costs are among the challenges. Green roofs are layered and incorporate interacting thermal processes. Green roof models are either based on the calculation of thermal transmittance (U-values), an experimental energy balance, or data-driven (primarily neural network) approaches. U-values were calculated for eight hypothetical scenarios consisting of four non-insulated and four insulated roofs, with or without semi-intensive and intensive green roofs of various materials and layer thicknesses. While the non-planted, non-insulated roof had the highest U-value, planted roofs were particularly effective for non-insulated roofs. Three of these scenarios were in reasonable accord with experimental and theoretical thermal transmittance literature values. Finally, a non-insulated planted roof, particularly one with rockwool, was found to provide a certain degree of thermal insulation in comparison to a non-planted insulated roof. [ABSTRACT FROM AUTHOR]

In these days of heightened environmental consciousness, many countries are shifting their focus towards renewable energy sources for both large-scale uses (such as power plants that generate electricity) and smaller-scale applications (e.g., building heating and cooling). In this light, it is not surprising that there is a growing interest in technologies that are reliant on non-conventional sources of power, such as geothermal energy. This study is making an effort to provide a comprehensive understanding of the possible advantages and multiple uses of geothermal energy systems, in the context of their technical and environmental evaluation through Life Cycle Assessment. A brief description of the analyzing methods and the tools used to study a particular system or application is presented. The geothermal technologies and the applications of specific systems are discussed in detail, providing their environmental advantages and their technical barriers as well. District and domestic heating systems cover a significant fraction of the geothermal energy potential. The majority of the discussed studies cover the electricity production as the most important application of geothermal energy. The overall conclusion of the current work is that geothermal energy is an extremely viable alternative that, combined with other renewable energy systems, may mitigate the negative effects of the existing energy mix worldwide. [ABSTRACT FROM AUTHOR]

With growing urban populations, methods of reducing the urban heat island effect have become increasingly important. Cool pavements altering the heat storage of materials used in pavements can lead to lower surface temperatures and reduce the thermal radiation emitted to the atmosphere. Cool pavement technologies utilize various strategies to reduce the temperature of new and existing pavements, including increased albedo, evaporative cooling, and reduced heat conduction. This process of negative radiation forces helps offset the impacts of increasing atmospheric temperatures. This paper presents an extensive analysis of the state of the art of cool pavements. The properties and principles of cool pavements are reviewed, including reflectivity, thermal emittance, heat transfer, thermal capacity, and permeability. The different types, research directions, and applications of reflective pavements are outlined and discussed. Maintenance and restoration technologies of cool pavements are reviewed, including permeable pavements. Results show that cool pavements have significant temperature reduction potential in the urban environment. This research is important for policy actions of the European Union, noting that European and international business stakeholders have recently expressed their interest in new ways of reducing energy consumption through technologically advanced pavements. [ABSTRACT FROM AUTHOR]

The present article utilizes wind measurements from three buoys data collection stations in Ionian Sea to study the wind speed and power characteristics using the Weibull shape and scale parameters. Specifically, the site dependent, annual, and monthly mean patterns of mean wind speed, Weibull parameters, frequency distribution, most probable wind speed, maximum energy carrying wind speed, wind power density and wind energy density characteristics have been analyzed. The Weibull distribution was found to represent the wind speed distribution with more than 90% accuracy, in most of the cases. Moreover, the correlation between the percentages of times the wind speed was above cut-in-speed and the measured mean wind speed for the three selected sites, as the correlation between the aforementioned percentages and the scale parametercwere examined and were found linear. At all these sites, no definite increasing or decreasing trends in annual mean wind speed values could be detective over the data reporting period. The mean values of wind speed, scale parameter, most probable wind speed, maximum energy carrying wind speed, wind power and wind energy density values showed higher values during winter time and lower in summer time in Pylos and Zakynthos. Moreover, Pylos and Zakynthos were found to be the best sites from wind power harnessing point of view. [ABSTRACT FROM AUTHOR]

Motivated by the international tendency to improve the urban microclimate, minimize building energy consumption and improve air quality, this paper carries out a literature review of the Urban Heat Island (UHI) effect throughout the world with the main goal of reporting its intensity and understand its determining factors. Items reported for each study include: time duration, location and population of cities studied, number and type of data collecting stations, descriptive temperature measurements estimated and warming trend per unit of time. Variables that appear to influence the UHI included latitude and elevation; climate characteristics, surface morphology, vicinity to bodies of water, distance from industrial sites, urbanization, vegetation cover, land usage, presence of impervious surfaces, presence of urban canyons, building density, distribution and consumption of heating or cooling energy, building ventilation as well as road traffic intensity and urban air pollution. Difficulties arose from the fact that data were collected under different conditions and protocols and the conclusions have mostly local validity while the size and significance of the UHI was inversely associated with inhomogeneity adjustments. All in all, observations point to significantly higher urban temperatures than the surrounding rural environment with temperature records suggesting an upwards trend in both urban and rural measurements, strongly related to urbanization and vegetation. The UHI intensity was usually significant during warm periods and increased in both minimum and maximum temperatures. It was concluded that the UHI effect varied as to the city size, land use, topographic factors, vegetation, urbanization, and industrialization, season of the year and time of day as well as the prevailing meteorological conditions. [ABSTRACT FROM AUTHOR]

High urban temperatures are observed during the last 100 years due to the heat island phenomenon. The effect is intensively pronounced even in small-sized cities by temperature differences between rural and urban environment up to 6oC. In order to keep the phenomenon under control, mitigation strategies, especially concerning cool roofs have been established. Under hot and arid climates, roof temperatures reach almost 70oC and about 50% of heat enters into buildings through roof slab. The aim of this paper is to present the heat island phenomenon in a small city of Western Greece and to propose energy-saving techniques that improve the overall energy performance of building stock and are easy to be applied. [ABSTRACT FROM PUBLISHER]

The paper presents a design and operation analysis of an Integrated Collector Storage (ICS) solar water heater, which consists of an asymmetric Compound Parabolic Concentrating (CPC) reflector trough, while the water tank comprises two concentric cylinders. The annulus between these vessels is partially depressurized and contains a small amount of water in the bottom of the outer vessel which dominantly contributes to the heat transfer from the outer to the inner cylinder. A multi-criteria optimization algorithm is applied to re-evaluate the design specifications of the parabolic surface, thus modifying the design of the entire ICS system and predict the necessary number of units for achieving the highest possible effectiveness with minimized fabrication costs and environmental impacts. The environmental footprint of the device is assessed through Life Cycle Assessment (LCA). The produced thermal energy in conjunction with the environmental and economic results are evaluated as a function of different configuration parameters regarding the water storage conditions, the solar radiation and the total pressure inside the annulus. The ultimate aim of the evaluation process is to offer new perspectives on the design principles of environmentally friendly and cost-effective devices with improved thermal performance. [ABSTRACT FROM AUTHOR]

During the last years much research has taken place about urban heat island (UHI) effects, mainly concentrated in big cities with an extended gap for the smaller. The aim of the paper is to present the analysis results of an urban heat island research taking place in a small city of Western Greece, Agrinio. The specific research target was to validate the presence of the UHI, measure its intensity and determine the parameters that correlate with the appearance of the UHI. A network of air temperature sensors was developed in 8 different places in the city and measurements were recorded every 10 minutes for a period of 6 months. Data from a meteorological station were also collected for the same period. Results show that the city of Agrinio presents strong UHI intensities during the night with high values up to 6°C and a mean of 3.82 °C. During the daytime, cool island effect is also observed for about 35% of day duration. Temperature differences appear to be strongly correlated with the dominating wind speed in the city since air plays an important role in urban ventilation and creates more homogeneous temperatures in urban spar. [ABSTRACT FROM AUTHOR]

This paper utilizes three hourly measured values of wind speed and direction from seven buoys data collection stations in Aegean Sea to study the wind speed and power characteristics applying the Weibull shape and scale parameters. Specifically, the site dependent, annual and monthly mean patterns of mean wind speed, Weibull parameters, frequency distribution, most probable wind speed, maximum energy carrying wind speed, wind power density and wind energy density characteristics have been studied. The Weibull distribution was found to represent the wind speed distribution with more than 90% accuracy in most of the cases. Slightly decreasing trends were observed in annual mean wind speed values at Lesvos and increasing at Mykonos. The mean values of wind speed, scale parameter, most probable wind speed, maximum energy carrying wind speed, wind power and wind energy density values showed higher values during winter time and lower in summer time. Mykonos was found to be the best site from wind power harnessing point of view. Moreover, the correlation between the percentages of times the wind speed was above cut-in-speed and the measured mean wind speed for the three selected sites and the correlation between the aforementioned percentages and the scale parameter c were examined and were found linear. [ABSTRACT FROM AUTHOR]

The design, installation and operation of an Automatic Weather Station (AWS) are described and analysed in the present paper. This station of high endurance is easy to be installed and capable for long-time operation without significant problems. The metadata of the station which are the characteristics of the instruments, electronic logic control and datalogging systems are described in detail, according to the Guides of the World Meteorological Organization (WMO). Moreover, a computer controlled environment is designed and implemented, with capabilities of data acquisition and control with flexible and high performing software and hardware capabilities. The AWS can easily communicate, so directly as remotely, with some modifications and both possibilities are examined in detail. Finally, an evaluation procedure is presented and analyzed, while the obtained results are used for testing the system. The evaluation depicted the unique and well established characteristics of the system and proved its potential application to meteorological data collection and calculation. [ABSTRACT FROM AUTHOR]

The present study deals with various techniques aiming primarily to improve the environmental and microclimatic quality of urban areas, and, secondly, to minimize the energy consumption in the buildings' sector based mainly on bioclimatic principles and criteria in the same area. The selected techniques, which include the re-use of treated wastewater effluents using the wastewater treatment plan, as well as solar passive heating/cooling techniques, have' been applied in a specific urban area located in Patras, a large city of western Greece. The application of the treated wastewater effluents re-use in urban areas is possible through the combined reuse of the treated municipal wastewater effluents indoors for domestic use, as well as for irrigating plants in outdoor spaces. One building of the area was selected as representative, and its thermal behavior was simulated and analyzed primarily in its existing situation, and, furthermore, after using several passive cooling techniques, such as the installation of a green roof system, the use of insulating materials in the external walls and roof, the insertion of an atrium, night ventilation techniques, etc. The obtained results showed that with regards to the cooling load, the application of night ventilation and a green roof system provided the higher energy saving, while with respect to the heating load, the more efficient improvements were the insulation on the building's external walls and roof. [ABSTRACT FROM AUTHOR]

Bamboo is known as a sustainable alternative for green building design, and it has been tied culturally to some regions around the world. However, bamboo's structural strength for different design scenarios needs more investigation before it is widely adopted. Timber and bamboo have similar mechanical properties, but the latter is a repaid, renewable, sustainable, disaster-resilient system and is versatile, which has more advantages for construction purposes. Natural bamboo and its derivatives have been considered as a high-demand green and environmentally responsible alternative construction material, and this interest is increasing globally. Because of the rapid growth rate and large developing area, it is more useable than the limited timber resource. However, natural bamboo has an anisotropic and nonhomogeneous material property, which varies in multiple directions. There is limited engineering data and investigation of bamboo material and its use in and impact on construction. In this study, three different bamboo models were analyzed by Strand7; each of them had different features in structure and in the major construction material. A new model was proposed by improving the three given structures and was maximized in the mechanical capacity. Some design guidelines were proposed based on the analysis and comparison of different bamboo structures. The model will replace natural bamboo with bamboo scrimber, which is an engineered bamboo derivative that has more uniform material properties. [ABSTRACT FROM AUTHOR]

In recent decades, the steady increase of energy consumption from building construction and operations cause atmospheric pollution and significant financial burden, mainly due to the high costs imposed from energy production. This study examines ways under which modern designs of a building can be applied on construction and domestication while following conventional methods of construction, compared to a building that has been constructed and domesticated under bioclimatic architecture. Particularly, two buildings were investigated in terms of the energy consumption incurred, being built on the same seaside area and period of construction and at adjacent plots of the same distance from sea for ease of comparison. The first building (A1) was constructed under the principles of bioclimatic architecture, being also facilitated with green and smart technologies. The second building (A2) was constructed under conventional construction techniques. The energy efficiency of both buildings was calculated by the "TEE KENAK" software, while specific parameters were recorded. Energy classifications of both buildings were valued and a proposed scenario and interventions unveiled the energy classification upgrading from A2 to A1. Our analysis revealed, as also found in the literature, that during thermal energy oscillating conditions, corresponding relative humidity stresses were observed, indicating that the vapor pressure handling should be taken into account towards comfort. The preliminary incremental cost evaluation and comparison of A1 and A2 energy upgrading under the criterion of simple payback period were critically discussed. [ABSTRACT FROM AUTHOR]